The present invention relates to an air flow rate measuring device for an internal combustion engine which measures the flow rate passing through an intake air passage in an intake system, and particularly to a thermal type of air flow rate measuring device.
In a prior art shown in Japanese Patent Application Laid-Open No. 4-212022, an air passage body in which an air flow rate measuring device is provided is divided from an air cleaner. Further, members which constitutes a sub-passage is integrated with the air passage body, and a driving circuit and the sub-passage in a module part is not integrated.
In the above prior art, since the air passage body and the air cleaner are not integrated, a lot of parts are required. Further, because the direction of air flow is not controlled, it is impossible to measure the air flow rate with high accuracy.